FFmpeg create boomerang GIF effect from video trimmed Flutter

I have a 45seconds video file which I want to create a boomerang GIF from a trimmed part of the video, let's say from 20s to 23s.

I tried to run in flutter a basic GIF command :

" -i $videoInput -filter_complex ${"[0]reverse[r];[0][r]concat=n=2:v=1:a=0"} $gifOutput";

But it was crashing every time without a short video file (OOM) :

INFO: frame=  362 fps= 15 q=-0.0 size=  162048kB time=00:00:12.06 bitrate=110074.4kbits/s speed=0.514x
INFO: Skipping NAL unit 62
INFO: Skipping NAL unit 62
INFO: Skipping NAL unit 62
INFO: Skipping NAL unit 62
 * thread #50, queue = 'com.apple.root.default-qos', stop reason = EXC_RESOURCE RESOURCE_TYPE_MEMORY (limit=3072 MB, unused=0x0)
    frame #0: 0x0000000250474d60 libsystem_platform.dylib`__bzero + 64
libsystem_platform.dylib`__bzero:
->  0x250474d60 <+64>: dc     zva, x3
    0x250474d64 <+68>: add    x3, x3, #0x40
    0x250474d68 <+72>: subs   x2, x2, #0x40
    0x250474d6c <+76>: b.hi   0x250474d60               ; <+64>
Target 0: (Runner) stopped.

Questions :

• Can the video be trimmed and the boomerang GIF created in the same command ?

• Can the GIF in the same command be scaled down (as compression for low res files) ?

• Can preset like veryfast or medium be used for GIF creation or only for video ?

Thanks in advance for any help